None.
1. Field of the Invention
The present invention is for a chemical vapor deposition reactor, and, more specifically, is for a chemical vapor deposition reactor incorporating gas flow vortex mixing action for uniform chemical vapor deposition upon a stationary wafer substrate. Gas flow including chemical vapors is introduced in tangential fashion to the interior of the heated reactor to provide for suitable uniform rotation of the gas field within the reactor and create a uniform boundary layer over the stationary wafer substrate.
2. Description of the Prior Art
Prior art reactors used for chemical vapor deposition on a wafer substrate often incorporated rotating heated chucks which held the wafer substrate which was rotated into the path of oncoming chemical vapor emanating from a multiple orifice injector device often referred to as functioning similarly to a shower head. Proximity of the heated rotating chuck to the multiple orifice injector device caused undesired heating of the multiple orifice injector device to cause the chemical vapor to decompose at high temperatures. As a result, chemical vapor was turned into particulate matter which clung to and which was deposited in the multiple orifices, thereby causing clogging of the orifices to cause flow restriction and improper chemical vapor deposition on the wafer substrate. Such clogging required shutting down of the process so that the orifices could be cleaned. Also, because of poor temperature regulation, the chemical vapor would decompose and would be deposited on the sidewalls of the reactor, thereby causing inefficient operation which also required shutdown for cleaning purposes. Rotating heated chucks also required elaborate vacuum pumping schemes, and a way to transfer heat to the rotating heated chuck. The use of pyrometry and associated circuitry was also required to sense and control chuck temperature. Clearly what is needed is a CVD reactor which overcomes the problems found in prior art devices.
The general purpose of the present invention is to provide a reactor for deposition of chemical vapor onto a substrate wherein chemical vapors introduced into the reactor will disperse uniformly onto the substrate without the need for rotating or otherwise moving the substrate.
According to the present invention, the above stated general purpose is achieved by a vortex based CVD reactor including a reactor base, a reactor sidewall located above and secured to the reactor base, a top located above and secured and fitted to the reactor sidewall, injector tubes tangentially oriented and secured to the reactor top, a reactor interior comprised of the inner surfaces of the reactor base, reactor side walls and reactor top, a heated densified carbon susceptor located in intimate contact with a resistance heated chuck, a lift yoke and ceramic wafer substrate support pins, a robotic access port located in the reactor base, a positionable shutter aligned with the robotic access port, and an exhaust port located at the upper region of the reactor top. The tangentially oriented injector tubes serve to introduce chemical vapors into the reactor in tangential fashion, thereby creating spinning gas fields which cause a uniform boundary layer to form over the substrate whereby the chemical vapors deposit uniformly.
The reactive gas is introduced at or above its boiling point, and is caused to react at the substrate that is held at its higher, decomposition temperature.
One significant aspect and feature of the present invention is a CVD reactor which incorporates a vortex gas flow for the uniform deposition of chemical vapors upon a wafer substrate.
Another significant aspect and feature of the present invention is the use of tangentially located injector tubes at the reactor top for the introduction of chemical vapors to the reactor interior in tangential fashion.
Still another significant aspect and feature of the present invention is the chemical vapor deposition upon a wafer substrate which is stationary.
Yet another significant aspect and feature of the present invention is a CVD reactor having a minimum of moving parts.
A further significant aspect and feature of the present invention is a CVD reactor which eliminates or minimizes the deposit of particulates on the reactor components.
A further significant aspect and feature of the present invention is a CVD reactor having a positionable shutter to provide a non-interrupted reactor interior.
Having thus described an embodiment of the present invention and set forth significant aspects and features thereof, it is the principal object of the present invention to provide a vortex based CVD reactor.